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How to diagnose & cure black or dark stains on indoor walls, ceilings, carpets, floors: this article describes what to do about interior wall and ceiling thermal tracking stains, thermal bridging stains,
building air leaks, and building insulation defects.

We give detailed step by step suggestions for removing and preventing indoor stains caused by thermal tracking. We include diagnostic procedures to figure out why these stains appear, suggestions for cleaning or painting over indoor stains, and how to prevent their recurrence.

Question: How do I get Rid of Thermal Tracking Stains & Prevent Their Recurrence

I have what seems exactly how you describe thermal tracking on my
ceiling in the living room and some discoloration in other rooms. I
live in a twin ranch home in Philadelphia that is quite small/cozy for
a family of 8.
My question is what do I do to stop this discoloration from
continuing? I had someone go into the attic and he said that he never
saw black soot in an attic like he saw in mine - it was congregated
along the beams of the ceiling.

How do I get rid of it? My furnace was replaced less that 10 years
ago by a fellow who has a reputation for his meticulous work - the
furnace is also well maintained.
We are considering moving and I would like to repaint my house soon.
Any suggestions? - P.C.

Below we provider a quick summary of some thermal tracking stain clean up and prevention suggestions, followed by an in-depth article on this topic.

Wash stained surfaces: if your building walls and ceilings have paint in good condition it is usually possible to wash the surfaces, though you may need to make more than one pass to remove streaking, and ultimately you may simply decide to re-paint. Use a non-suds ing detergent intended for cleaning interior walls and ceilings. If cleaning is not sufficient you'll need to re-paint.

For thermal tracking stains on building insulation in an attic, no cleaning is necessary, just find and fix the air bypass leaks or missing insulation. As long as the insulation has not been wet (and at risk of mold contamination) surface staining from dust deposition by air movement across the insulation won't impact its effectiveness. But fixing the air leaks that left the dust there will indeed improve building insulation and energy efficiency, often significantly.

Watch out: if you try simply painting over dark thermal tracking stains the black stains may bleed through your new paint job. If necessary use a lacquer primer/sealer paint before your top coat. But before re-painting or even cleaning, some diagnosis of the cause of thermal tracking stains is important since if you don't correct the cause of this staining your newly cleaned walls or paint job may be at risk.

Identify the cause of thermal tracking: review the other sections of this article. Visual inspection of attics, wall cavities,
or other building areas can tell you if the building is un insulated or has openings where air is bypassing insulation. Be alert also for
building cavities where insulation has become wet and possibly moldy as such would need to be removed before continuing to improve the
insulation and air tightness of the home. And don't forget to be sure the stains you are examining are due to thermal tracking.
See Other Stains on Indoor Walls & Ceilings.

Add insulation to un insulated building cavities such as un insulated attics (first priority) or walls (second priority) and pay attention
to areas of air bypass leaks where insulation has been omitted, removed, or imperfectly installed. Identify areas in the building where there are air bypass leaks and seal them.
Air Bypass Leaks Marks on Insulation shows
how to recognize where air is moving past poorly installed building insulation.

Seal significant building air leaks against unwanted air movement such as openings at exterior trim, window perimeters, or at the floor/wall
or ceiling wall juncture. Thermal tracking stains that mark the location of building leaks or the location of ceiling joists and exterior wall studs are also marking the location of thermal bridging - points of building heat loss. Seal building air leaks and air bypass leak points between building floors. See these articles:

Review the building indoor moisture levels: since even a reasonably well insulated building may develop thermal tracking marks if
interior humidity is excessive. If the building has unwanted wet conditions such as a wet crawl space or basement or other areas of leaks, those
conditions need to be corrected.
See HUMIDITY LEVEL TARGET.

Review and reduce sources of indoor soot or debris such as an oil or gas fired heating system that is not working properly, since those conditions
need to be corrected for safety and economy of building heating as well. Since excessive use of most types of candles can also produce
unwanted levels of indoor soot, if those are a principal source of indoor stains their use should be reduced or eliminated.

Is the oil or gas fired heating system operating properly? If not it may be not only smoky or sooty, but also operating inefficiently and worse, it could be dangerous. A sooty gas boiler or furnace is very dangerous and should be shut down and serviced immediately.
See HEATING SYSTEMS for articles on heating system inspection, diagnosis, and repair.

Are there or have there been occupants who were smokers of cigarettes, cigars, pipes?

Are there fireplaces or woodstoves that release smoke to the interior?

Are building occupants smokers? Cigarette smoke is a big contributor to thermal tracking stains, often leaving heavy brown stains on building walls even where other stain sources are absent.

Most samples of thermal tracking particulate deposits that we examine in our forensic lab are simple house dust: a mixture of fabric fibers and skin cells. These are normal debris found indoors. But more frequent indoor cleaning, HEPA vacuuming, eliminating of or reducing the number of carpets, installation of glass fireplace doors, avoiding burning food on the stove, are additional examples of steps that can reduce the indoor airborne particulate level and thus the rate of staining on indoor surfaces.

Use a better grade washable paint when re-painting stained surfaces. That will make future surface cleaning easier.

Detailed Step by Step Guide to Curing Indoor Stains due to Thermal Tracking

1. Inspect and Diagnose Accurately to Find the Causes of Indoor Stains and Thermal Tracking

If your building diagnosis is not accurate there is a real risk of both wasting money and possibly failing to attend unsafe conditions such as mold contamination or unsafe heating appliance operation and dangerous carbon monoxide hazards. So it is important to determine why the stains are occurring, to rule out or address safety issues, and then we can proceed to a simple three step procedure.

Cure the underlying causes of staining and thermal tracking, such as by addressing sources of soot and dirt, sources building moisture, insulation defects, and ventilation problems. This step is addressed in detail beginning
at THERMAL TRACKING.

Clean, seal, and paint the stained areas. This step is addressed in this article, beginning above
at What to Do About Thermal Tracking and continuing in detail below.

Monitor for any new staining events and diagnose them

To be reliable a thorough building investigation to identify the causes and recommend cures for indoor stains and thermal tracking will examine the entire property, outside and inside, examining all readily accessible areas, examining the mechanical systems, (plumbing, heating, air conditioning), the building ventilation and insulation, and more. Focus of the inspection may be on the sources of soot and debris, moisture, as particle deposition sources, as well as on building conditions that cause particle deposition on surfaces: high indoor moisture, air movement, insulation and ventilation defects.

2. Indoor Staining and Other Cleanup/Removal Recommendations

Warning about harmful mold: if you hire a professional to address building staining and its cause and remedy this is not a contract not to address a mold or air quality investigation which is a more extensive (and more costly) procedure. For this reason significant mold contamination, health and safety risks, and significant mold remediation costs are likely to be faced at this property: these are conditions which were excluded from the scope of a site investigation for stains, thermal tracking, sooting, or heating and air conditioning problems.

Mold investigation: Where a building investigation shows that the property has had a history of leaks or moisture problems, and in some other cases, we recommend that you have a proper mold investigation performed as it is likely that the property faces significant mold cleanup cost.

Mold safety during building repairs: Because moldy materials are likely to be present, it is important that any property cleaning and repairs which you pursue be conducted properly and professionally in order to avoid increasing the safety and health risk to building occupants

MOLD EXPERT, WHEN TO HIRE -provides assistance in deciding when it is justified to hire a professional to inspect for mold and to prepare a mold remediation plan.

Warning about cleanup effectiveness: No cleaning measures will be effective, and the cost of performing them may be wasted, without also addressing causes of building contamination such as water entry, sewage backups, building leaks, and building ventilation defects.

Those defects which a professional inspection was able to identify are addressed at Exterior, Interior, and Mechanical System recommendations below and in the report specific to your building. Others may be discovered.

Cleanup and demolition can begin, but cannot be completed reliably until/unless the building is acceptably dry. If not all suspect areas are addressed it may be difficult to obtain a satisfactory clearance test following remediation work. If leaks or moisture remain or recur there is high risk of a problem.

Here are the basic steps in correcting an indoor sooting or thermal tracking problem

Demolition: remove wet, moldy, or water-damaged materials such as floor trim and moldy plaster/drywall where your investigation has found it in the building.

Additional removal of stained, soiled, or moldy material beyond that cited in this section should be continued where opened/removed material discovers additional moldy or suspect materials.

Remove building insulation wherever it is exposed by demolition. Remove insulation within 5 ft.

Since future repair, demolition or cleaning processes can disclose hidden problems, anyone performing these tasks should, as a matter of general practice, be alert for discovery of leaks, water entry, building damage, mold reservoirs etc.

Clean black-stained areas on ceiling and wall drywall using a non-phosphate commercial interior cleaner, after protecting floor surfaces and after moving out or protecting and covering furnishings.

Alternatively you can elect to paint black-stained areas using a stain-covering paint, in which case We recommend use of a lacquer primer sealer. Do not use a latex sealer as stains often bleed through water-based paints and even some oil-based paints. Bin™, or Enamelac™ are trade names of two lacquer primer-sealer paints that work in this application. Proper ventilation and other procedures are necessary for health and safety during this procedure.

Following cleaning and/or sealing in the stained areas, your painter can prime and paint the interior room walls and ceilings throughout. We recommend use of a vapor retarder primer paint on the inside surface of exterior walls and ceilings to reduce the moisture absorption into these materials in the future.

2.4. Investigate Stained buildings Further for Hidden Damage due to Moisture or Mold

Before stopping the demolition of damaged or moldy materials, be sure that all areas of known, visible, or most-suspect damage from leaks or moisture traps are opened and investigated. It is important that the extent of demolition continue sufficiently to see that no contaminated, moldy, insect-damaged, or rotted problem areas remain un-addressed.

Otherwise, there is a significant risk that the cost of this repair and renovation could be wasted by having to repeat the procedure later. Examples of such areas we noted during our inspection include:

While there could certainly be other problem areas as yet undiscovered on the building, the following points of extra risk particularly suggested themselves based on observations made at the site or history which was reported for the building. These are areas of further investigation should indoor air quality complaints persist after the remediation measures recommended in this report have been completed.

Our photo shows surface runoff or roof spillage that has entered a basement by running down the foundation wall. Unless this water source is corrected, the building will continue to suffer from excessive indoor humidity - a contributor to thermal tracking and soot staining.

See the exterior and interior observations made during your building inspection, as these correlated with risk of water entry, moisture, mold, and allergens.

Also see suggested items for repair or investigation under Exterior Recommendations, Interior Recommendation,Mechanical systemsRecommendation beginning at 3.0 below.

Leaks at skylights – in the ceiling area below the point of water entry at the skylight, in the ceiling at the top of the wall down-slope from the leak point, and in at least the top of the wall cavity just below this area; if leak damage is discovered by removing drywall in these spots, drywall should be removed to inspect lower areas such as at the floor and in the ceiling of any finished rooms below the floor in the same location.

Leaks at walls –

Leaks at floors – such as in a wet basement, where removal of material around the perimeter walls is necessary to be sure that all of the water entry points have been identified, diagnosed, and corrected.

Areas exposed by present or future demolition, repair, remodeling:

Back side of drywall on opposing side of abutting wall or ceiling cavities opened for demolition

Surface of framing, sheathing, sub-flooring exposed by demolition

These are optional targets for further investigation: I did not find significant leakage evidence or other evidence in these spots sufficient to strongly recommend immediate destructive inspection of these areas, but it may be more economical to address any such findings as part of the current cleanup plan rather than later.

Walls behind baseboards or other trim which have been left in place after flooding – if mold is found in these areas the wall cavities need to be opened for further exploration.

Other unopened wall and ceiling cavities, particularly in areas that have been wet such as where leaks occurred from plumbing, ice dams, leaks into walls below window sills, at radiators and plumbing fittings (toilet base, leaky or running toilets, fixture drains) wherever such areas of extra risk can be identified by building history or by visual observation

I observed exterior conditions which are associated with leaks, high moisture, or other factors which contribute to mold/allergens in buildings. Please review your site exterior photos (in your site investigation report) as they provide additional specific details. These items have or may have contributed to water entry, interior mold in the building. Correct these sources of leaks and moisture to prevent future water entry to prevent mold re-growth.

Maintain the gutters (loose, wrong slope, clogged, leaky), add drip edge or re-hang gutters if roof runoff runs behind gutters; extend downspouts at least 6ft. from the building and to locations that will drain away from the building; assure buried downspout lines are not clogged or leaking underground; correct improper in-slope grade which holds water against the foundation.

4.1. Interior inspection and recommendations specific to the subject property:

Besides items already cited above for cleaning or removal, I observed these interior conditions which are associated with mold/allergens in buildings. Please review your site interior photos attached to your thermal tracking and building inspection report as they provide specific details.

Use mold-resistant construction materials and methods when repairing or restoring building areas which are to be demolished for cleaning or for other renovation and repairs. Please see these articles which offer details of these flood response and mold resistant construction methods.

https://InspectAPedia.com/Fiberglass/Fiberglass_Mold_Contamination.php “Mold in Fiberglass Insulation” – We recommend against using fiberglass insulation in wall cavities in this building where you are insulating against masonry exterior walls, and We recommend placement of sound plastic vapor barriers on the warm side of all exterior walls when renovating or repairing

Wall to wall carpeting in the basement/below-grade level creates an ongoing risk of forming a mold reservoir. At the next event requiring cleaning or renovation, we recommend elimination of this material at this location, going to tile or vinyl flooring. Area rugs can still be used as these can be cleaned.

Fiberglass insulation in the basement/below-grade level creates an ongoing risk of forming a very significant mold reservoir – this is a condition I have been detecting frequently in buildings, even where the insulation looks clean to the eye.

At the next event requiring demolition, cleaning, or renovation, we recommend elimination of use of ordinary fiberglass insulation in moisture-prone building cavities such as basement walls against below-grade foundation walls. Use solid foam insulation products which do not themselves absorb moisture and which are less mold friendly.

Basement de-watering systems: if all of my outside recommendations have been completed correctly (and have been verified as complete and correct) and then water entry recurs it may be necessary to install an interior de-watering system.

In general we do not recommend this approach as building dampness may still be excessive—it is more effective to prevent water entry from outside whenever possible.

But sometimes outside measures are just impractical or more costly than an indoors basement or crawl space waterproofing project. Inside de-watering systems like B-Dri™ are a last resort. Basement waterproofing systems can be effective at keeping water off of the floors if they are properly installed.

Improperly installed a basement de-watering system or basement waterproofing system and can create its own dampness problems in buildings. See Sump Pumps just below.

Suspect upholstered furniture, curtains - either try professional steam cleaning followed by HEPA vacuuming or dispose of this furniture;

Scented candles – can be a respiratory irritant to many people. We recommend abandoning use of and disposing of these items.

4.3 How to Dry Out a Problem Crawl Space

Crawl space venting – this is a debated topic as in humid weather venting outside air into a cool crawl space might increase crawl space moisture.

We no longer recommend simple passive venting nor humidistat-controlled venting except in special circumstances. When my inspection indicates a long-standing moisture problem in such an area the best current advice is to stop venting the crawl space(s)s and to convert it/them to a dry, conditioned space:

Provide a moisture barrier over any dirt floors and extending up foundation walls but not up to nor in contact with wood framing or sills. Moisture barriers may be 6-mil poly or other special basement sealer products such as special moisture-sealing concrete coatings

Be sure that the dirt floor moisture barrier slopes to a drain. A great many installations we see, even in company product literature, show multiple low spots in a crawl space, each of which is subject to ponding and water retention from leaks or other unanticipated water entry into a crawl space or basement.

Install a continuous dehumidification system (with a permanent drain hookup so the system can run unattended. Use an A/C condensate pump to a building drain if a gravity drain connection is not feasible.

A dehumidifier in a crawl space will also provide some heat in that area; if the crawl space is too cold (despite perimeter insulation) it may be necessary to add a small level of heat there. Some building also permit introduction of dry heat into these areas.

See our detailed article CRAWL SPACE DRYOUT - home for more complete information on how to dry out a wet or damp crawl space in order to reduce the chance of mold, insect damage, allergens, and structural rot.

If fiberglass board or flex-duct was used, flooded, contaminated (see lab report), visibly moldy or badly soiled duct sections will need to be replaced as these components can’t be cleaned and in my opinion encapsulants are unreliable. If non-cleanable replacement duct materials (fiberglass and flex duct) are installed they may need to be replaced again in the future.

This may be cost-reasonable for accessible sections of flex duct but not for duct work run through building cavities or for major trunk lines. Watch out for incomplete-cleaning of duct-work; I often find mold growing where condensate collected in duct work is run through un-conditioned space such as a cool crawl space or hot attic.

Window and wall-mounted air conditioners: clean these units and replace or clean washable filters monthly during the in-use season. If mold appears inside the air path of these units they are probably not cleanable and will need to be replaced.

5.2. Plumbing & Other Systems or Equipment

Plumbing: Replace any corroded/leaky traps and where demolition exposes tub or shower traps assure those are sound before completing repairs. Watch for and repair any future plumbing leaks promptly.

Refrigerator: clean (using a HEPA vacuum) coils and grille as well as dust below and at other sides of the refrigerator. When cleaning the coil check that the evaporator tray is clean and that it is not spilling over. This is a common source of indoor mold and potentially Legionnaire’s disease.

Prevent future basement flooding: to reduce the risk of building flooding during severe storms and storm drain backup I have these related suggestions that you should consider:

Outside water: Repair and monitor possible outside sources of leaks and water entry I’ve already cited, as part of ongoing building maintenance and monitoring

Check valves: Install check valves in any basement or other low-level drains to assure that during severe weather and local flooding you do not have water entering the building through backing up sewers, septic system piping, or storm drains

Sump pumps: Install battery-backup sump pump system to assure that should water nonetheless appear in the basement level, it can be removed from the building during an emergency, even if electrical power is temporarily lost. See our Sump Pumps guide at https://InspectAPedia.com/septic/Sump_Pumps.htm

6. General Notes on Sooting, Stains, and Mold Stain Prevention

Mold on drywall can not normally be cleaned sufficiently as portions of the mold growth are inside the gypsum and paper. Except in the case of trivial soil or mold on a painted drywall surface, replacement is the effective means of remediation for this material. Material removal is more reliable than simple surface disinfection, but steps must be taken to avoid contaminating the building with construction dust and mold spores.

Check/remove baseboard trim at floors: where floors or wall cavities have been flooded I often find mold growth on the back of baseboard or door trim, and on either or both sides of drywall or plaster where trim was installed; don’t assume that there is no mold in a wall cavity or that there is no mold behind wood trim just because no mold is visible on the wall surface.

Avoid mold growth: Reduce or eliminate the conditions that encourage mold and fungal growth. In any building where there is recurrent water entry, there is risk of the conditions which produce or amplify mold growth.

Depending on species, mold spores may die or become dormant, failing to reproduce, at low moisture levels. If the building is sufficiently damp or wet again, mold growth will probably recur.

Always identify and correct obvious outside sources of water entry before going to the expense of costly basement waterproofing systems, though in some cases such systems may be necessary.

Install a high-capacity dehumidifier and run it until basement moisture is in the 45-55% range. You may want to purchase an inexpensive relative-humidity indicator for this purpose. (See Radio Shack products.) You can drain the dehumidifier by a condensate pump or to a sump pit so it can run unattended (except for periodic cleaning).

Missing backup condensate drain – can be compensated-for by installing a leak detection system in the condensate tray. This design will shut down the A/C system if a leak is detected, preventing water damage to the building from this source.

Reader Question: Is there a professional whom we can contact for help in curing thermal tracking stains?

First of all, I want to say thank you! Your site is the ONLY site that I was able to find the answer to what is wrong with my house. I now know that I have Thermal Tracking. My question to you is: Is there a professional that I can contact to take care of this problem? What type of person would do that? My home is 12 years old and we’ve been dealing with this every since we bought it. We did not build it, but purchased it from a couple that had lived here for only one year. Thank you for your help! - Cindy

Drafts that move extra air across some surfaces can also be a factor in thermal tracking stain location. (See AIR LEAK DETECTION TOOLS)

Simple cleaning and painting will of course remove or cover the stains from thermal tracking. But unless the cause of these stains is corrected as well, they will return.

The optimum "fix" for these indoor stains on walls and ceilings and even sometimes on floors or carpets near walls (Floor Carpet Thermal Tracking Stains) is to improve building insulation, but of course that's the most costly step too, but then again, improving insulation returns savings in lower heating or
cooling costs for the building as well as increased comfort.

Short of improving insulation you can find and fix sources of excessive indoor moisture, stop using scented candles or other indoor burning things that produce soot, and improve housekeeping (better, HEPA-rated vacuum cleaner, for example) so that the level of house dust is reduced. And of course find and fix air leaks and drafts.
An experienced home inspector or energy auditor (EXPERT DIRECTORY) should be able to help you track down and prioritize the locations and causes of the four thermal tracking stain factors I listed above.

Reader question: trouble painting over stains: keep bleeding through

(June 29, 2014) Colleen said:

I have used primer to cover thermal tracking marks on wall studs and ceiling joists on interior walls only to have them reappear. What should I do to remedy the problem? Black marks, which follow studs and ceiling joist only on the sheetrocked exterior walls, continue to show through primed and painted walls. There have never been any improperly burning heaters, wood-burning stoves, non-vented heating appliances...used in the home. Interior walls are not affected.

Reply: use a lacquer primer sealer when painting over black stains on interior walls

Colleen, the reappearance of stains through some paints is a common and annoying problem. Usually the root problem is that the stain is bleeding through a water soluble paint or on occasion even through an alkyd paint or primer.

Try a lacquer primer sealer such as "Bin" or "Enamelac" or if those are not handy, spray the stains with a coating of spray shellac - clear or white if you prefer. When that's dry you should be able to paint over with your primer and not see the bleed-through.

Thermal tracking marks will of course recur if we don't also address it root causes: indoor dust or debris levels, moisture, uneven or missing insulation.

Reader follow-up:

I have taken up all carpet and floor coverings to replace with hardwood, had all ductwork cleaned and will continue to monitor indoor moisture and dust levels. Hopefully this is the last time I have to prime all interior walls and ceilings before painting. Ceilings are equally as affected by the streaking/sooting effect.

Do you know of any issue related to having two layers of vapor barrier inside walls contributing to this problem? The house was built in 1976 and is very well insulated, but side walls have foil-coated insulation batting between the studs and plastic on top of that, next to the sheetrock. One contractor suggested that may be contributing to the problem, saying a home should have one or the other but not both. The ceilings, however, have only plastic for a vapor barrier and are still equally as stained as the walls. It seems to make sense to me that the root cause would be related to dust/debris, moisture... that you suggested, versus an improper vapor barrier. Your thoughts?

Reply:

Colleen

Indeed we don't want to create a vapor-barrier "sandwich" with insulation between;

In a heating climate the vapor barrier goes on the warm side of the wall - the interior surface of the wall studs over which drywall is installed.

In a cooling climate the vapor barrier goes on the warm side of the wall too but that becomes the exterior surface of the wall.

Frequently Asked Questions (FAQs)

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Question:
what is the best top coat sealant or paint to use over stains

(Jan 14, 2015) Marian Heller said:

Can I paint a lacquer primer or apply a coating of spray shellac over Zinsser 1-2-3? I recently moved into a friend's apartment and it badly needs painting. My friends are serious candle burners, and there are dark outlines around all the places where pictures and artwork hung, throughout the apartment. Started with the bedroom - swept and wiped down the walls after using compound to repair the various places in the room where the paint was falling off the wall ....then applied primer .... painted the ceiling Sat and the walls Sunday. When we went to remove the tape about an hour after painting, both the ceiling paint and the wall paint lifted/fell off in a sheetlike way. I was thinking that perhaps years of oily candle residue made the walls 'slippery,' and it would explain why the primer didn't even stick to the ceiling. OR maybe we didn't remove dust from sanding compounded areas, tho in a patch test afterward of the wall cleaned with tack cloth, primer still didn't stick. The Zinsser primer said don't use TSP, so we didn't wash walls beforehand.

Investigating, I found your website. There are ghost marks all over the apartment -- could that be why primer isn't sticking? Also, I've already primed hallway, which has black ghost marks all over it. Can I apply lacquer primer sealer over the primer (or spray shellac), or do I have to do something to remove it (if so, what? sanding?).
Thanks for your help!! At least we didn't paint the entire apartment before finding out about this!
Warm regards,
Marian

Reply:

I looked at the photos you sent by email - it looks as if there was a water or moisture or other problem; indeed this is a severe paint adhesion loss problem.

Before repairing or repainting I would make sure there were no leaks into ceilings or walls since if there were you have other investigation to do before painting.

After being sure there is no in-cavity damage or that there are nor were leaks there, you can clean with a TSP substitute, let dry thoroughly, then you can paint with a lacquer primer-sealer and then a finish coat and you should be OK.

If there were leaks - ever - into building cavities, especially where mold-friendly materials such as wood, drywall, paper, gypsum board, paint, some insulation products, were used, then some investigation of those cavities for hidden mold or damage would be in order.

(Jan 15, 2015) Anonymous said:
thanks Daniel! The super is coming by for a moisture reading tomorrow, so I'm investigating leaks. Can I clean and apply the lacquer primer-sealer right over the one wall (different room than the disaster site) that has Z 1-2-3 primer, as well as walls I've not yet primed? thanks!

Reply:

I've had good success using a lacquer type primer sealer over surfaces that had persistent grease bleed-through staining. As long as you 've done basic surface cleaning it's usually OK. Rarely we find a wall stain that itself is dissolved-by and leaks through the lacquer.

Beware of water-based stain killers that work fine on many surfaces but don't seal as universally as lacquer-based products.

Question: Ghosting stains in New York City

(Mar 31, 2015) Ghosting in NYC said:
I seem to have ghosting on an interior wall of a bedroom that is adjacent to an exterior wall. I believe that the wall may be poorly insulated but I have no idea. What type of professional/expert do I need to hire to confirm that there is ghosting and to perform the necessary repairs? I am confused as to whether I should consult a home inspector, an engineer, a general contractor, some other expert, etc. Thanks!

Reply:

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Thanks to Stacy O.
for asking for clarification on the causes, spacing, and what to do about thermal tracking Sept Nov 2007

Thanks to Penina C. for discussing clean-up and prevention of indoor thermal tracking stains, October 2010.

ASHRAE resource on dew point and wall condensation - see the ASHRAE Fundamentals Handbook, available in many libraries. The following three ASHRAE Handbooks are also available at the InspectAPedia bookstore in the third page of our Insulate-Ventilate section:

Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.

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TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & AssociatesSpecial Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.

Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

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